Antihypercholesterolemic tri-yne carbonates

ABSTRACT

The compounds of the following general structural formula (I) ##STR1## wherein R is hydrogen or a pharmaceutically acceptable salt thereof, are β-ketoacyl-coenzyme A thiolase inhibitors and are useful as antihypercholesterolemic agents for the treatment of disease in which the inhibition of cholesterol biosynthesis would be useful, such as arteriosclerosis, hyperlipidemia and familial hypercholesterolemia.

SUMMARY OF THE INVENTION

This invention relates to the novel pharmacological properties of the compounds of the formula (I) which have been found to be β-ketoacyl-coenzyme A thiolase inhibitors and are useful as antihypercholesterolemic agents either as the sole therapeutic agent or in combination with bile acid sequestrants.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to a method of inhibiting cholesterol biosynthesis which comprises the administration to a subject in need of such treatment a nontoxic therapeutically effective amount of a compound represented by the following general structural formula (I): ##STR2## wherein R is hydrogen or a pharmaceutically acceptable salt thereof.

The present invention is also directed to a method of inhibiting the activity of β-ketoacylcoenzyme A thiolase enzymes which comprises the administration to a subject in need of such treatment a nontoxic therapeutically effective amount of a compound represented by the general structural formula (I). Specifically, the compounds of this invention are useful as antihypercholesterolemic agents for the treatment of arteriosclerosis, hyperlipidemia, familial hypercholesterolemia and the like diseases in humans.

They may be administered orally or parenterally in the form of a capsule, a tablet, an injectable preparation or the like. It is usually desirable to use the oral route. Doses may be varied, depending on the age, severity, body weight and other conditions of human patients but daily dosage for adults is within a range of from about 20 mg to 2000 mg (preferably 20 to 100 mg) which may be given in two to four divided doses. Higher doses may be favorably employed as required.

The pharmaceutically acceptable salts of the compounds of this invention include those formed from cations such as sodium, potassium, aluminum, calcium, lithium, magnesium, zinc, and from bases such as ammonia, ethylenediamine, N-methyl-glucamine, lysine, arginine, ornithine, choline, N,N'-dibenzylethylenediamine, chloroprocaine, diethanolamine, procaine, N-benzylphenethylamine, diethylamine, piperazine, tris(hydroxymethyl)aminomethane, and tetramethylammonium hydroxide.

The compounds of this invention may also be coadministered with pharmaceutically acceptable nontoxic cationic polymers capable of binding bile acids in a non-reabsorbable form in the gastrointestinal tract. Examples of such polymers include cholestyramine, colestipol and poly[methyl-(3-trimethylaminopropyl)imino-trimethylene dihalide]. The relative amounts of the compounds of this invention and these polymers is between 1:100 and 1:15,000.

The intrinsic acetoacetyl-coenzyme A thiolase, a β-ketoacyl-coenzyme A thiolase enzyme, inhibition activity of the compounds of this invention is measured by the standard in vitro protocol described hereinbelow:

Acetoacetyl-Coenzyme A Thiolase Inhibition

(a) The enzyme was prepared from the livers of Sprague Dawley rats treated one week with 0.075% lovastatin in the diet to induce the enzyme. Acetoacetyl-coenzyme A thiolase was purified through the DEAE-Cellulose step essentially as described by Mehrabian, et al. (See Mehrabian et al., J. Biol. Chem. 261:16249-16255, 1986). This procedure was modified slightly by carrying out the 30%-50% ammonium sulfate precipitation of the enzyme and a dialysis prior to the DEAE-cellulose step. As described by Mehrabian, et al., (See Mehrabian et al., J. Biol. Chem. 261:16249-16255, 1986), the 0.06 M eluate contained the acetoacetyl-coenzyme A thiolase. The sample was concentrated by ammonium sulfate precipitation, dissolved in the buffer used for elution and stored at -70°.

(b) Inhibition of acetoacetyl-CoA thiolase was measured by coupling the formation of acetoacetyl-CoA to its subsequent reduction to β-hydroxybutryl-CoA by β-hydroxybutryl-CoA dehydrogenase. The oxidation of NADH was followed in a Gilford spectrophotometer (Model #250) at 340 nm.

The incubation contained 71.4 mM Tris-HCl, pH 7.5, 0.71 mM EDTA, 10.7 mM MgCl₂, 0.53 mM dithiothreitol, 0.21 mM NADH, 0.016 units of β-hydroxybutryl-CoA dehydrogenase, 16.2 μg of acetoacetyl-CoA thiolase, the indicated concentrations inhibitor dissolved in DMSO and water to make a volume of 0.140 ml. This solution was incubated until a stable base line was achieved. The reaction was initiated by the addition of 10 μl of acetoacetylCoA to give a concentration of 2.85 mM. The reaction was measure at room temperature for a time period necessary to produce a measurable reaction rate.

The IC₅₀ of 5-(1-hydroxy-2,4,6-heptatriynl)-2-oxo-1,3-dioxolane in this system was 1×10⁻⁸ M. (IC₅₀ is the concentration that inhibits 50 percent of the acetoacetyl-Coenzyme A thiolase activity, which is a β-ketoacyl-coenzyme A thiolase enzyme.)

Tissue Culture Assay

Human Hep G2 cells were grown in 25 cm² flasks in the presence of Mimimal Essential Media (Gibco) and 10% fetal calf serum. Forty-eight hours before the experiment the cells were switched to serum-free Higuchi medium (See Higuchi, K., J. Cell Physiol. 75:65-72, 1972). Incubations were carried out in the Higuchi medium containing the free acid of formula I, 1-[¹⁴ C] sodium acetate (1 mci/35.7 mg), 2 uci/ml, and 5-[³ H] mevalonate lactone (5 uci/umole), 5 uci/ml. After 3 hours the reaction was stopped by aspiration of the media and rinsing the cells three times with 3 ml of saline. The cells were treated for 30 minutes with 2 mls of 1 N NaOH and then this mixture was transferred to screw cap tubes which were heated at 95° for 1 hour. A portion (0.2 ml) was removed for protein determination by a Microbiuret method (See Zamenhof, S., Methods Enzymol. 3: 702, 1957), the remainder of the solution was acidified with 0.2 ml of concentrated HCl and extracted 3 times with 4 ml each of petroleum ether. The petroleum ether extracts were combined, evaporated to dryness under nitrogen and redissolved in 0.2 ml of ethyl acetate. An 0.1 ml aliquot was chromatographed on silica gel-G thin layer plates which were developed in petroleum ether-diethyl ether-acetic acid (75:25:1). The plates were stained with iodine and those areas corresponding to standard cholesterol, oleic acid and squalene were scraped into scintillation vials; 10 ml of Aquasol 2 was added and their radioactivity determined. The IC₅₀ of 5-(1-hydroxy-2,4,6-heptatriynyl)-2-oxo-1,3-dioxolane was 2×10⁻⁶.

The compound of formula I can be prepared by growing under controlled conditions the microorganism ATCC-53614, ATCC-53615 or ATCC-53616, with ATCC-53614 being preferred because it produces the largest quantities of the compound of Formula I. The compound is obtained by fermentation of one of said microorganisms followed by isolation of the compound, all as described hereinbelow.

Based upon taxonomic studies, ATCC-53615 and ATCC-53614 are new strains of the species Streptoverticillium hiroshimense. ATCC-53616 is a strain of the genus Nocardia. A sample of ATCC-53614, ATCC-53615 and ATCC-53616 has been deposited, without restriction as to availability, in the permanent culture collection of the American Type Culture Collection at 12301 Parklawn Drive, Rockville, Md. 20852 and have been assigned the accession numbers that such microorganisms have been referred to herein.

The morphological and cultural characteristics of ATCC-53614, ATCC-53615 and ATCC-53616 are as follows:

(V=vegetative growth, A=aerial mycelium, SP=soluble pigment) ATCC-53615

Morphology: Sporophores form short branches produced in a verticil or whorl at intervals along the aerial mycelium. These branches in turn produce several secondary branches that form straight chains of 10-15 spores. Spores are cylindrical, 0.9×1.2-1.7 microns. Spore surface is smooth.

Yeast extract-malt extract agar (ISP Medium 2)

V: Reverse - dark brown with vectors of dark red

A. Deep pink mixed with red and rose-beige vectors

SP: None

Oatmeal agar (ISP Medium 3)

V: Reverse - dark brown with vectors of dark red

A: Velvety, dark pink with pinkish-white & rose-beige vectors and red flecks

SP: None

Inorganic salts-starch agar (ISP Medium 4)

V: Reverse - dark reddish brown with vectors of deep pink

A: Deep pink mixed with rose-beige and white

SP: None

Glycerol asparagine agar (ISP Medium 5)

V: Reverse - dark reddish brown

A: Rose-beige with vectors of deep rose

SP: None

Peptone-iron-yeast extract agar (ISP Medium 6)

V: Brown

A: None

SP: Medium brown

Melanin: Dark brown pigment produced in tryptone-yeast extract broth, light brown pigment produced in tyrosine agar and peptone-iron-yeast extract agars

Tyrosine Agar (ISP Medium 7)

V: Reverse - brown edged with reddish-brown

A: rose-beige mixed with pink and white

SP: Medium brown

Czapek-Dox Agar

V: Colorless, flat

A: Sparse, white

SP: None

Carbon utilization

Pridham-Gottlieb basal medium (ISP Medium 9)+1% carbon source;

    ______________________________________                                         + = growth; ± = growth poor or questionable;                                - = no growth as compared to negative control (no                              carbon source)                                                                 ______________________________________                                                 Glucose +                                                                      Arabinose                                                                              -                                                                      Cellulose                                                                              -                                                                      Fructose                                                                               ±                                                                   Inositol                                                                               +                                                                      Lactose ±                                                                   Maltose +                                                                      Mannitol                                                                               -                                                                      Mannose +                                                                      Raffinose                                                                              ±                                                                   Rhamnose                                                                               -                                                                      Sucrose ±                                                                   Xylose  ±                                                           ______________________________________                                    

Temperature range (Yeast extract-dextrose+salts agar)

28° C.--Good growth and sporulation

37° C.--good vegetative growth; moderate aerial growth

42° C.--Moderate vegetative growth; no aerial

50° C.--No growth

Oxygen requirements (Stab culture in yeast extract-dextrose+salts agar)

Aerobic

All readings taken after three weeks at 28° C. unless noted otherwise. pH of all media approximately neutral (6.8-7.2).

Color number designations taken from Color Harmony Manual, 1958, 4th Edition, Container Corporation of America, Chicago, Illinois.

ATCC-53614

Morphology: Sporophores form short branches produced in a verticil or whorl at intervals along the aerial mycelium. These branches in turn produce several secondary branches that form straight chains of 10-15 spores. Spores are cylindrical, 0.9×1.2-1.7 microns (970×). Spore surface is smooth (TEM).

Yeast extract-malt extract agar (ISP Medium 2)

V: Reverse - dark red

A. Rose-beige

SP: None

Oatmeal agar (ISP Medium 3)

V: Reverse - deep red

A: Rose-beige

SP: None

Inorganic salts-starch agar (ISP Medium 4)

V: Reverse - deep red

A: Rose-beige

SP: None

Glycerol asparagine agar (ISP Medium 5)

V: Reverse - dark brown with flecks and vectors of deep red

A: Pinkish-beige mixed with white and vector of deep pink

SP: None

Peptone-iron-yeast extract agar (ISP Medium 6)

V: Tan with red flecks

A: None

SP: Lt. brown

Melanin: Positive on peptone-iron-yeast extract agar and tryptone - yeast extract broth

Tyrosine Agar (ISP Medium 7)

V: Reverse - dark red with vectors of lighter red

A: Pinkish-white with vectors of light pink

SP: very light brown

Czapek-Dox Agar

V: moderate, white

A: moderate, white

SP: None

Carbon utilization

Pridham-Gottlieb basal medium (ISP Medium 9)+1% carbon source;

    ______________________________________                                         + = growth; ± = growth poor or questionable;                                - = no growth as compared to negative control (no                              carbon source)                                                                 ______________________________________                                                 Glucose +                                                                      Arabinose                                                                              ±                                                                   Cellulose                                                                              -                                                                      Fructose                                                                               +                                                                      Inositol                                                                               +                                                                      Lactose ±                                                                   Maltose +                                                                      Mannitol                                                                               +                                                                      Mannose +                                                                      Raffinose                                                                              ±                                                                   Rhamnose                                                                               -                                                                      Sucrose ±                                                                   Xylose  ±                                                           ______________________________________                                    

Temperature range (Yeast extract-dextrose+salts agar)

28° C.--Good growth and sporulation

37° C.--Moderate growth and sporulation

42° C.--No growth

50° C.--No growth

Oxygen requirements (Stab culture in yeast extract-dextrose+salts agar)

Aerobic

All readings taken after three weeks at 28° C. unless noted otherwise. pH of all media approximately neutral (6.8-7.2).

Color number designations taken from Color Harmony Manual, 1958, 4th Edition, Container Corporation of America, Chicago, Ill.

ATCC-53616

Morphology: Vegetative hyphae were fully developed with branching. Fragmentation of hyphae occured in older cultures.

Yeast extract-malt extract agar (ISP Medium 2)

V: Reverse - dull golden yellow

A. Moderate, whitish

SP: None

Oatmeal agar (ISP Medium 3)

V: Tan

A: sparse, grayish white

SP: None

Inorganic salts-starch agar (ISP Medium 4)

V: Reverse - dull golden-yellow

A: Moderate, white to creamish-white

SP: None

Glycerol asparagine agar (ISP Medium 5)

V: Tan

A: Sparse, whitish

SP: None

Peptone-iron-yeast extract agar (ISP Medium 6)

V: Tan

A: None

SP: None

Melanin: Negative

Tyrosine Agar (ISP Medium 7)

V: Tan

A: None

SP: None

Czapek-Dox Agar

V: Very thin, colorless growth

A: None

SP: None

    ______________________________________                                         Carbon utilization                                                             Pridham-Gottlieb basal medium (ISP Medium 9) + 1%                              carbon source; + = growth; ± = growth poor or                               questionable; - = no growth as compared to                                     negative control (no carbon source)                                            ______________________________________                                                 Glucose +                                                                      Arabinose                                                                              -                                                                      Cellulose                                                                              -                                                                      Fructose                                                                               +                                                                      Inositol                                                                               +                                                                      Lactose -                                                                      Maltose +                                                                      Mannitol                                                                               -                                                                      Mannose +                                                                      Raffinose                                                                              -                                                                      Rhamnose                                                                               -                                                                      Sucrose -                                                                      Xylose  -                                                              ______________________________________                                    

Temperature range (Yeast extract-dextrose+salts agar)

28° C.--Good vegetative and aerial growth

37° C.--Good vegetative; sparse aerial

42° C.--No growth

50° C.--No growth

Oxygen requirements (Stab culture in yeast extract-dextrose+salts agar)

Aerobic

All readings taken after three weeks at 28° C. unless noted otherwise. pH of all media approximately neutral (6.8-7.2).

It is to be understood that for the production of the compound of formula I, the present invention is not limited to the use of ATCC-53614, ATCC-53615 or ATCC-53616. It is especially desired and intended to include the use of natural or artificial mutants produced from the described organisms, or other variants of ATCC-53614, ATCC-53615 or ATCC-53616 as far as they can produce the compound of formula I. The artificial production of mutants may be achieved by a conventional operation such as X-ray or ultraviolet (UV) radiation, or by the use of chemical mutagens such as; nitrogen mustards, nitrosoguanidine, camphor and the like, or by means of recombinant DNA technology.

The compound of formula I can be produced by utilizing a preserved source of ATCC-53614, ATCC-53615 or ATCC-53616 under controlled aerobic conditions in a liquid nutrient medium as follows. The preserved source is utilized to inoculate a liquid nutrient medium containing sources of carbon, nitrogen, phosphorus, calcium and magnesium and other elements necessary for life. This medium is incubated at 28° C. The flask containing the culture and liquid nutrient medium is incubated with agitation on a rotary shaker at 220 RPM. After 48 hours, when growth is abundant, the culture growth is used to inoculate a flask containing a medium which supports production of the product.

These production media are inoculated with the culture growth and are incubated at 28° C. for 4 days with agitation at 180 to 220 RPM, most often 220 RPM.

Such media contain carbon sources such as glycerol, dextrose, cottonseed oil, cod liver oil or corn gluten. They contain nitrogen and sulfur sources such as beef extract, yeast extract, ardamine pH, Edamine, Hycase and corn gluten. Also included are inorganic ions such as calcium, as well as some inert materials as celite.

In order to isolate the compound of Formula I, the fermentation broth must be clarified by filtration. The compounds of interest reside in the broth filtrate. The crude product may be purified by chromatography using an appropriate adsorbent such as polymeric organic based resins such as Amberlite XAD-2 or Mitsubishi HP-20, silica gel and hydroxypropyl cross linked dextran gels such as Pharmacia LH-20. The compound of Formula I is eluted from the adsorbents with suitable solvents or mixture of solvents. Solvent extraction is also used.

The following examples illustrate the preparation of the compound of the invention and should not be construed as limiting the invention.

The composition of media employed in the following examples are listed below. Media are prepared in a 250 ml Erlenmeyer flask. The contents are sterilized with steam at 121° C., 15 pounds pressure for 20 minutes.

    ______________________________________                                         BAM II & Celite                                                                Yeast Extract     1        g.                                                  Beef Extract      1        g.                                                  Hycase            2        g.                                                  Glucose           10       g.                                                  MOPS              11.6     g.                                                  Celite            5        g.                                                  Distilled H.sub.2 O                                                                              1,000    ml.                                                 pH                7.0-7.2  using NaOH                                          NPA-2                                                                          Corn Gluten       5        g.                                                  Edamine           2.5      g.                                                  Yeast Extract     5        g.                                                  Glucose           10       g.                                                  CaCO.sub.3        5        g.                                                  Distilled H.sub.2 O                                                                              1,000    ml.                                                 pH                7.2-7.4  using NaOH                                          KH                                                                             Tomato Paste      20       g.                                                  Primary Yeast     10       g.                                                  Dextrin           20       g.                                                  CoCl.sub.2.6H.sub.2 O 5                                                                          g.                                                           Distilled H.sub.2 O                                                                              1,000    ml.                                                 pH                7.2-7.4  using NaOH                                          KE                                                                             Dextrose          1        g.                                                  Starch            10       g.                                                  Beef Extract      3        g.                                                  Ardamine pH       5        g.                                                  NZ Amine Type E   5        g.                                                  MgSO.sub.4.7H.sub.2 O                                                                            0.05     g.                                                  Phosphate Buffer  2.0      ml.                                                 CaCO.sub.3        0.5      g.                                                  Distilled H.sub.2 O                                                                              1,000    ml.                                                 pH                7.0-7.2  using NaOH                                          Phosphate Buffer                                                               KH.sub.2 PO.sub.4 91       g.                                                  Na.sub.2 HPO.sub.4                                                                               95       g.                                                  Distilled H.sub.2 O                                                                              1,000    ml.                                                 pH = 7                                                                         LP                                                                             Beef Extract      6        g.                                                  Glycerol          8.0      ml.                                                 Cottonseed Oil    1.0      ml.                                                 Cod Liver Oil     1.0      ml.                                                 Ardamine pH       0.4      g.                                                  Distilled H.sub.2 O                                                                              1,000    ml.                                                 pH = 7.0                                                                       ______________________________________                                    

EXAMPLE 1 Preparation of the Compound of Formula I (I) (a) Fermentation of ATCC-53614

A culture of ATCC-53614 is inoculated from an L-tube (lyophilized tube) into a 250 ml baffled erlenmeyer flask containing 44 ml of KE seed medium and grown for two days at 28° C. and shaken in a rotary shaker (2 inch throw) at 220 rpm. Two ml of the grown seed medium is then inoculated into a 250 ml unbaffled erlenmeyer flask containing about 54 ml of the production media LP and grown at 28° C. and shaken in a rotary shaker (2 inch throw) for four days at 220 rpm. The compound of formula I is contained in this broth.

(b) Fermentation of ATCC-53615

A culture of ATCC-53615 is inoculated from an L-tube into a 250 ml erlenmeyer flask containing 54 ml of BAMII and celite seed medium. The flask is incubated at 28° C. and shaken in a rotary shaker (2 inch throw) at 220 rpm for 48 hours. Then 10 ml from this flask is used to inoculate a two liter baffled erlenmeyer flask containing 250 ml of NPA-2 production medium. This flask is incubated at 28° C., and shaken in a rotary shaker (2 inch throw) for 96 hours at 180 rpm. The compound of formula I is contained in this broth.

(c) Fermentation of ATCC-53616

A culture of ATCC-53616 is inoculated from an L-tube into a 250 ml baffled erlenmeyer flask containing 54 ml of KE medium. The flask was then placed on a rotary shaker (2 inch throw) and shaken at 220 rpm for 2 days in a 28° C. room. Two ml of the broth were then used to inoculate a 250 ml unbaffled erlenmeyer flask containing 44 ml of KH medium. This flask was then placed on a rotary shaker (2 inch throw) at 28° C. and shaken for four days at 220 rpm.

(II) Isolation of the Compound of Formula I

The compound of formula I can be isolated from each of the broths of ATCC-53614, ATCC-53615 and ATCC-53616 by the following procedure. It should be noted that the following isolation procedure can be utilized for varying volumes of whole broth by adjusting proportionately the volumes of the solvents and adsorbents.

Example: Isolation of the Free Acid of Formula I

(a) Approximately 2180 L of whole broth from a fermentation batch was harvested at 48 hours. The broth was clarified by filtration using Supercel as a filter aid, followed by a water wash. The 2200L filtered broth at pH7 was adsorbed on 120L of Mitsubishi Diaion HP-20 resin at 4L/minute. The resin was washed with 120L of distilled deionized water at the same rate. Antibiotic activity was eluted from the resin with 15×10L fractions of 60:40 acetone-water. The rich eluate fractions (5-12) were combined (80 L) and extracted with 2×80 L ethyl acetate. Extract 1 (130 L) and extract 2 (100 L) were combined and dried over anhydrous sodium sulfate. The drying agent was removed by filtration and the filtrate was concentrated under vacuum to 3.75 L. The concentrated extract contained 6.5 g of the free acid of Formula I at about 5% pure.

(b) 800 ml of ethylacetate extract (approximately 1.39 g of the free acid of formula I) from Step (a) was evaporated to an oily residue and immediately taken up in methylene chloride to a volume of 100 ml. The methylene chloride solution was applied to a 200 g column of E. Merck silica gel grade 62 (60-200 mesh), equilibrated in methylene chloride. The column was washed with 2×500 ml of methylene chloride and then eluted with 5:95 methanol-methylene chloride, taking 250 ml fractions. The free acid of formula I was eluted with the 5:95 methanol-methylene chloride. Fractions 3 and 4 contained 1.0 g (˜70% yield) of the free acid of formula I at ˜10% pure.

(c) The silica gel rich eluates 3 and 4 from Step (b) were evaporated to about 12 ml (methanol) 120 ml of methylene chloride and 120 ml of hexane was added to provide the feed for a 900 ml Pharmacia Sephadex LH-20 column equilibrated in 10:10:1 hexane-methylene chloride-methanol. After a 360 ml void volume fraction, four 900 ml (1 column volume) fractions and 30×250 ml fractions were collected. Based on HPLC and bioassay, fraction 13-25 (250 ml each) contained 0.9 g of substantially pure free acid of formula I.

(d) Due to the instability of the free acid of formula I to concentration, an alternate method was used to provide concentrated solutions. LH20 fractions 13-25 from Step C, 3250 ml, was extracted with 500 ml of 0.1 M potassium phosphate buffer pH 7.2. The compound was extracted into the aqueous layer, 620 ml, which was reextracted with 200 ml of methylene chloride at pH 4.5. The methylene chloride extract was dried over anhydrous sodium sulfate. The extraction volumes could be adjusted to provide varying concentrations of the free acid of the compound of formula I in methylene chloride.

(e) Preparation of Sodium Salt of the Compound of Formula I

In order to provide aqueous solutions of the sodium salt, of the compound of Formula I, the following method was used. 110 ml of LH-20 rich cut (10:10:1) was extracted with 50 ml of water, the pH carefully adjusted to 7.5 with dilute sodium hydroxide. The aqueous layer was evaporated under reduced pressure to remove residual organic solvent, yielding an aqueous solution of the sodium salt of the compound of formula I.

III Analytical Data

All three isolates were shown by HPLC and HRMS to be identical.

Analytical data for the compound of formula I isolated from ATCC-53616 is as follows:

1. Mass Spectral Data

Mass spectral data were obtained on MAT 212 mass spectrometer at 90 ev in the electron impact mode. High resolution data were obtained on the same instrument using the peak matching method. HRMS gave a molecular formula C₁₇ H₁₈ O₆. T₂ (calc. 462.1894; found 462.1882) upon trimethylsilylation with pyridine: BSTFA (1:1) at 100° C. for 1 hour. Abundant mass ions were found at m/z 175.0574 corresponding to C₇ H₃ O.T₁ (calc. 175.0579). [T=C₃ H₈ Si=72.0395].

2. ¹ H NMR Spectrum

The spectrum is in FIG. I. The spectrum has been recorded in CD₂ Cl₂ at ambient room temperature on a Varian XL400 spectrometer. Chemical shifts are shown in ppm relative to tetramethylsilane (TMS) at zero ppm using the solvent peak at δ5.32 as internal reference.

3. ¹³ C NMR Data

The spectrum was recorded in CD₂ Cl₂ at ambient room temperature at 75 MHz on a Varian XL400 spectrometer. Chemical shifts are given in ppm relative to tetramethylsilane at zero ppm using the solvent peak at 53.8 ppm as internal reference.

In agreement with HRMS data, 17 carbons are observed with the following chemical shifts: 24.4, 24.8, 28.90, 28.95, 33.8, 34.8, 59.0, 63.2, 64.3, 67.7, 69.0, 71.9, 72.9, 78.7, 81.7, 154.1, 178.0 ppm.

Infrared Data

A difference infrared spectrum was measured in dichloromethane on a Nicolet FT-lR instrument, model 7199. Strong bands were observed at 1806 (carbonate) and 1742 (COOH) cm⁻¹. 

What is claimed is:
 1. A method of inhibiting cholesterol biosynthesis which comprises the administration to a subject in need of such treatment a non-toxic therapeutically effective amount of a compound represented by the following structural formula: ##STR3## wherein R is hydrogen or a pharmaceutically acceptable salt thereof.
 2. The method of claim 1 for the treatment of arteriosclerosis, hyperlipidemia, or familial hypercholesterolemia.
 3. The method of claim 2 in which a daily dosage of from about 20 to 2000 mg of active ingredient is administered.
 4. The method of claim 3 in which the active ingredient is administered with a pharmaceutical carrier.
 5. The method of claim 4 in which the administration is oral.
 6. The method of claim 4 in which the administration is parenteral.
 7. A method of inhibiting the activity of a β-ketoacyl-coenzyme A thiolase enzyme which comprises the administration to a subject in need of such treatment a nontoxic therapeutically effective amount of a compound represented by the following structural formula: ##STR4## wherein R is hydrogen or a pharmaceutically acceptable salt thereof.
 8. The method of claim 7 wherein said β-ketoacyl-coenzyme A thiolase enzyme is acetoacetyl-coenzyme A thiolase.
 9. An antihypercholesterolemic composition useful in the treatment of arteriosclerosis, hyperlipidemia or familial hypercholesterolemia comprising a therapeutically effective amount of at least one compound having the formula ##STR5## together with a polymer selected from the group consisting of cholesyramine, coletipol and poly(methyl-(3-trimethylaminopropyl)imino-trimethylene dihalide, wherein R is hydrogen or a pharmaceutically acceptable salt thereof, and wherein the relative amounts of the compound and the polymer is between 1:100 and 1:15,000. 